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Conservation Agriculture in Southern
Africa- Assessing its Potential to
Respond to Climate Change
By Christian Thierfelder
Outline of this presentation
• Conservation agriculture – its benefits and challenges
• Some research evidence
• Research gaps and needs
• Introduction
• CA and Climate-smart agriculture
Traditional farming systems in southern Africa
Based on mouldboard plough or hand hoe
Largly focussed on maize (50-80% of land area) often planted in monoculture
Mostly rainfed systems
Farming systems are diverse, sometimes with intensive crop/livestock interactions
Crop residues are burned, grazed, or fed to animals
Farmers rarely use improved varieties and/or mineral fertilizer (<10kg ha-1 NPK in SSA)
Farmers still use a lot of manual labour
Large cropping areas are on inheritantly poor sandy soils
The predominant climate is very variable
The Challenges in Africa
Source: Sonder, unpublished
Projected change in agriculture productivity, 2080
Source: Hugo Ahlenius, UNEP/GRID-Arendal.
Climate change mitigation
What do we understand by Climate-smart Agriculture (CSA)?
CSA
Is this a useful concept?
….are not all agriculture systems
climate-smart?
What practices could be lumped under the CSA umbrella?
Conservation agriculture
Agroforestry (CAWT)
Rangeland management
The use of drought-tolerant germplasm
Water harvesting technologies
Targeted fertilizer application
Improved cattle feeding
Alternate wetting and drying in rice
….
There is not one CSA practice….
but different and complimentary
combinations of practices to achieve the
greatest CSA potential in a landscape!
Agroforestry
Nutrition security
Poverty alleviation
Natural resource management
Improved cook-
stove
Conservation
agriculture
Increased yields
Soil quality & carbon
Reduced
degradation &
erosion
Dietary diversity
Intercropping
Market access
Increase income
Participatory approach
Landscapes with multiple CSA options
What is Conservation Agriculture?
CA comprises the following principles:
• Minimal soil movement
• Surface crop residue retention
• Crop rotations and green manure cover crops
•Basin planting
•Jab-planter •AT Direct seeder
•Dibble stick
•Hoe-planter •Magoye ripper
CA - a flexible system….
New Developments for Africa....
CIMMYT‘s Research Focus in Southern Africa
Is conservation agriculture (CA) a more
profitable, viable and sustainable system than conventional agriculture?
What are the biophysical challenges to productive CA systems and how can they be overcome?
How climate-smart is CA in the context of
southern Africa
What socio-economic factors and
circumstances affect the adoption and outscaling of CA systems in southern
Africa?
Why focus on Conservation Agriculture?
CA reduces soil and land degradation
CA can help to adapt production to climate variability
and change ….!
CA is more water-, nutrient-, and energy-use-efficient
CA improves the productivity of
current farming systems
Some research evidence….
Conventional tillage Conservation agriculture
First rains ….
Conventional ridge tillage Conservation agriculture
In season….
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n in
mm
h-1
0
10
20
30
40
50
60
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100
110
120
130
Conventional ploughing - Maize
CA- Dibble stick, Maize
CA- Dibble stick, Maize-Cowpea
Chitedze, Malawi
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n (
mm
h-1
)
0
10
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Conventional ploughing, maize
Rip-line seeded, maize
Direct seeding, maize
Rip-line seeded, maize-cowpea
Henderson, Zimbabwe
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n (
mm
h-1
)
0
10
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CA- Direct seeding, maize
Conventional ploughing, maize
CA- Direct seeding, maize after sunflower
Sussundenga, Mozambique
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n r
ate
(in
mm
h-1
)
0
10
20
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40
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130
Direct seeding, maize-cotton
Conventional ploughing, maize
Direct seeding, maize-cotton-sunnhemp
Direct seeding, maize
Monze, Zambia
Infiltration is crucial in CA systems!
Soil moisture, 0-60cm, MFTC, 2011/2012
Date
07/1
1/11
21/1
1/11
05/1
2/11
19/1
2/11
02/0
1/12
16/0
1/12
30/0
1/12
13/0
2/12
27/0
2/12
12/0
3/12
26/0
3/12
09/0
4/12
Ra
infa
ll (
mm
d-1
)
0
10
20
30
40
50
60
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80
Availab
le s
oil m
ois
ture
(m
m)
0
20
40
60
80
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120
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160
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200
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240
Conventional ploughing, maize (CP-M)
Direct seeding, maize (DS-M)
Direct seeding, maize-cotton (DS-MC)
Rainfall 2011/2012
Yield gain DSM: 27% DSMC: 53%
CA performance in a wet and dry year, Malawi, 2007/08 and 2011/12
Ma
ize
gra
in y
ield
(kg
ha
-1)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
4018
4948 4789
Conventional ridge tillage
CA + sole maize
CA + maize/legume intercropping
Wet year 2007/2008
2485
40864223
Dry year 2011/12
+23% +19%
+64% +70%
Mitigation potential
Data on soil carbon
sequestration inconclusive
Some studies report benefits, some not…..!
Carbon accumulation often
observed in the first 0-30 cm but not in deeper layers
Few studies on GHGsSoil carbon dynamics, Monze FTC, 2005-
2010
0-30 cm
Year
2004 2005 2006 2007 2008 2009 2010 2011
0
5
10
15
20
25
30
35
Conventional agriculture, maize
CA, maize
CA, maize-cotton rotation
CA, maize-cotton-sunnhemp rotation
Harvest year
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
Ma
ize
gra
in y
ield
(k
g h
a-1
)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Conventional ploughing, maize (CPM)
Ripline seeding, maize (RIM)
Direct seeding, maize (DSM)
a
NS
b
b
NS
NS
aa
a
a
ab
b
b
a
a
a
b
a
a
b
a
a
b
a
a
b
a
CA performance on replicated on-farm trials –
Monze 2005-2016
Conventional tillage yield (kg ha-1
)
0 2000 4000 6000 8000 10000
Co
nse
rvati
on
ag
ricu
ltu
re t
rea
tmen
t yie
ld (
kg
ha
-1)
0
2000
4000
6000
8000
10000
1 :2 li
ne
1:1
line
Planting basins, Mozambique
Ripline seeding, Zambia
Manual direct seeding, Mozambique
Direct seeding, Zambia
Manual direct seeding, Malawi
Manual direct seeding, intercrop., Malawi
Ripline seeding, Zimbabwe
Direct seeding Zimbabwe
Thierfelder et al. 2015a
Regional yield response to CA in southern Africa from 2005-2016
Potential yield gains through combinations of technologies, Mozambique, 2009-2014
Maize grain yield (t ha-1) Yield gain (%)
Conventional agriculture
CA-Direct seeding
Traditional variety no fertilizer 1.47 1.79 21Traditional variety with fertilizer 2.50 2.95 18Improved OPVs with fertilizer 3.42 4.01 17Improved Hybrids with fertilizer 4.01 4.78 19
+225%
Thierfelder et al. 2015b
0 500 1000 1500 2000 2500 3000
Ridge & furrowMaize continuous
Dibble stick Maizecontinuous
Dibble stick-
Maize/Cowpea intercrop
Dibble stick-Maize -Cowpea rot
low
ra
infa
ll &
me
diu
m e
lev
atio
n
2012/2013 2013/2014 2014/2015 2015/2016
Net benefits (in USD)
Manual Sustainable Intensification Practices -Net Benefits (2012-2016), Eastern Zambia
Mutenje et al. 2016
0 500 1000 1500 2000 2500
CP maize sole
Ripper Maize Sole
Ripper Maize soybeanRotation
Hig
h r
ain
fall
& m
ed
ium
ele
vat
ion
2012/2013 2013/2014 2014/2015 2015/2016
Net benefits (in USD)
Mechanised Sustainable Intensification Practices Net Benefits (2012-2016)
Eastern Zambia
Mutenje et al. 2016
CP-maize CA-maize CA-maize/legume
La
bo
ur
days
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
2nd Weeding
Land clearing
Ridging
Sowing
Mulch appl.
Basal fertilizer appl.
Herbicide appl.
1st Weeding
3rd Weeding
Top dressing
Harvesting
Thierfelder et al. 2015b
El Nino response potential
• CA responds better to seasonal dry-spells leading to yield benefits of 30-60%
• Combined use of drought-tolerant maize with CA can
improve the performance of maize by more than 80%
• CA can improve incomes by 40-100% under drought
El Niño season 2015/2016….
Reduced yield variability under
conservation agriculture
0
200
400
600
800
1000
1200
1400
0
1000
2000
3000
4000
5000
6000
2010 2014 2018 2022 2026 2030 2034 2038
An
nu
al R
ain
fall
(mm
)
Mai
ze g
rain
yie
ld (
kg/h
a)
Years
rainfall Yield CP Yield CA
Ngwira et al. 2014
Climate changemitigation
Is Conservation Agriculture really “climate-smart”?
CSA
If it is so good – why are not all
farmers adopting conservation
agriculture?
Challenges still persist….
Residues: How can we feed both livestock and crops?
Weeds if no herbicides are used
Lack of fertilizer – what are the alternatives?
Donor driven adoption - one-size fits-all approaches
(S)low adoption – understanding the issues
Knoweldge gaps and perceptions amongst farmers
Lack of evidence and data taking – believe in myths
Targeting the wrong systems to the wrong
farmers
Ignoring farmers rationale and decision making
The need for co-development of technologies
What are the Gaps and Needs for the coming years?
What is the climate-smart
agriculture potential of CA at a larger scale (4p1000)
The need for more system‘s research
Mechanization!
What kind of CA is actually
adopted (quality assessment)-why is it disadopted?
How can we overcome
barriers to adoption?
More Gaps and Needs….!
What are the socio-economic impacts of CA on livelihoods, nutrition and gender
How can farmer-decision-making be better understood
Targeting of CA (e.g. to different farmers, farm types, agro-
ecologies)?
Research on Scaling – how can we increase the uptake
beyond small plot levels?
Expanding the niche –through successful scaling
Lead farmer approach
Demonstration and field days
Mother and baby trials
Innovation systems approach
Participatory extension approaches
Farmer-to-farmer exchange
Farmer field schools
ICT
Thank you
for your
interest!
Photo Credits (top left to bottom right): Julia Cumes/CIMMYT, Awais
Yaqub/CIMMYT, CIMMYT archives, Marcelo Ortiz/CIMMYT, David Hansen/University of Minnesota , CIMMYT archives, CIMMYT archives (maize), Ranak Martin/CIMMYT, CIMMYT archives.
